Very low battery life on new Sony C series

Is it Vista or is t the new C series but batery life on the C2Z/B is very poor - only 2.5 hrs using internet and e-mail on a new computer -0 could it be Vista or is it the core 2 duo that is the problem - Otherwise apart forbattery life and a hughe power brick tis is a good notebook

Anyone with XP on a C series to compare battery life ?

 

Battery and Power Adapter

Sony quotes the battery life of the included 6-cell battery at 3.0-4.5 hours of use depending on how you use the notebook. In my test of using the notebook at half screen brightness, wireless off, and idling for 2 hours and then light usage (typing in Word) for 1 hour I got exactly 3 hours of use. So that falls on the low-end of Sony's claim, and if I were doing anything during that 2 hours of idle time you'd get less battery life. You can get a 9-cell battery ($299) for a longer usage time unplugged, but the 9-cell will stick out from the back and add weight to the system.

From: http://www.notebookreview.com/default.asp?newsID=3390&Review=Sony+VAIO+C

 

It looks about right, check the reviews on it, it barely topples 3 hours when at half brightness with wireless off and only typing in word.